1. Field of the Invention
The present invention relates to a shaft supporting apparatus for a planetary gear reduction device.
2. Prior Art
A known Prior apparatus is illustrated in FIG. 1. In FIG. 1, a driven shaft 1 is mounted between a pair of rotatable radial ball bearings 3 and 4 within the planetary gear reduction housing 2. The planetary gear assembly partially shown in FIG. 1 is a simple planetary reduction device. Such an arrangement is generally used for other types of planetary gear reduces such as differential gear and compound planetary differential reduction devices. In such an arrangement, in the presence of an exerted radial force P on the driven shaft 1 outside the housing 2, the counterforces R.sub.1 and R.sub.2 are respectively supported by bearings 3 and 4. Therefore, the distance 1 between the two bearings 3 and 4 is dependent on and must be increased with an increase of the exerted radial force P. But increasing the distance 1 does nothing to improve the functioning of the planetary gear device. It just results in the requirement for a longer shaft and a thicker and heavier weight gear reduction housing.